1. Field of the Invention
The present invention relates generally to a magnetic disk drive, and more particularly to a negative pressure type head slider for a magnetic disk drive.
2. Description of the Related Art
In recent magnetic disk drives with decreasing size and increasing storage capacity, it has been desired to reduce the flying height of a head slider and realize contact recording/reproduction such that the head slider flies a microscopic height from a recording medium such as a magnetic disk or comes into contact with the recording medium. To reduce the flying height of the head slider, the surface roughness of the surface of the magnetic disk must be reduced. In a contact start and stop (CSS) type magnetic disk drive heretofore widely used, a flying surface of a magnetic head slider comes into contact with a magnetic disk upon stoppage of rotation of the magnetic disk, and flies above the surface of the magnetic disk during rotation of the magnetic disk by the action of an air flow produced in concert with the rotation of the magnetic disk.
In the CSS type magnetic disk drive, high flying stability and microscopic flying height (on the order of submicrons) can be ensured. However, the air bearing surface (flying surface) of the head slider comes into contact with the magnetic disk upon stoppage of rotation of the magnetic disk, and slides relative to the magnetic disk at starting and stopping the disk drive. To cope with this, a protective film formed of a hard material such as carbon and a lubricating layer for reducing the friction and wearing of the protective film to improve the durability of the magnetic disk are formed on a recording layer of the magnetic disk. Although the friction and wearing of the protective film can be reduced by the presence of the lubricating layer, there is a possibility of stiction between the magnetic disk and the head slider in the rest condition of the magnetic disk, causing a problem that the disk drive cannot be started.
With a recent increase in amount of information, the recording density or storage capacity of the magnetic disk drive is remarkably increasing and the size of the magnetic disk drive is remarkably decreasing. The size reduction of the magnetic disk drive is accompanied by a decrease in torque of a spindle motor in the disk drive, and the disk surface of the magnetic disk is smoothened for the increasing recording density. Due to these factors, much attention is now focused on the stiction problem causing a defective operation. As measures against this stiction problem, it has been proposed to apply texture forming by laser to a CSS zone of the magnetic disk or provide a plurality of projections on the flying surface (air bearing surface) of the head slider, thereby reducing a contact area between the head slider and the disk surface.
A negative pressure type magnetic head slider is widely used in recent magnetic disk drives, so as to reduce the flying height of the magnetic head slider from the magnetic disk. Such a negative pressure type magnetic head slider has a groove for generating a negative pressure by expanding air once compressed near an air inlet end of the head slider. In the magnetic disk drive using the negative pressure type magnetic head slider, there is a possibility that dust or dirt may be deposited on the bottom surface of the groove of the head slider in the CSS operation or seek operation, and when the amount of dust or dirt deposited exceeds a permissible amount, it may fall onto the disk surface to cause head crash.